An infra-red remote device is used to transmit commands and other signals to a remote electronic device. An infra-red remote unit functions by transmitting infra-red light from the transmitter unit to a receiver in the target device such as a set-top-box. The infra-red light is varied in a predetermined code in response to the operator's command or as a function of the information being transmitted. For example, a keyboard that is attached to a computer system by a cable communicates to the computer system by translating the keyboard entries into electrical signals that are transmitted through the cable. The electric signals are transformed into a data signal that is understood and implemented by the computer system. An infra-red remote keyboard performs in an analogous manner, but instead translates the keyboard entries into infra-red electromagnetic energy that is transmitted to a set-top-box. The set-top-box then transforms the infra-red signal into a data signal that is understood and implemented by the computer system.
The use of infra-red remote units to transmit commands from the operator to an electronic device includes familiar applications such as television remote controls, and cable television and satellite television control boxes. In addition, the use of infra-red remotes is expanding to include many new applications. Computer peripherals, such as computer keyboards (as discussed above), cursor directing devices (e.g., a mouse device), and infra-red printers, are increasingly using infra-red to communicate with computer systems in lieu of a cable connection. Also, hand-held devices, such as those commonly referred to as "palm-tops," rely on infra-red signals to download quantities of information into computer systems. Infra-red remote units are thereby advantageous because they eliminate the cables between devices that would otherwise be needed. Infra-red units are also advantageous because they facilitate greater freedom of movement by the user. Thus, the use of infra-red remote units provides a convenient and user-friendly method of communicating with electronic systems, especially as the complexity of both the receiving unit (e.g., a computer system) and the transmitting unit (e.g., a palm-top) increases.
The growing number of applications of infra-red remote units and peripheral devices consequently increases the number of different remote units and peripherals utilized by the operator (e.g., a consumer). For example, a typical consumer may have an infra-red remote unit for transmitting commands to a television, another remote unit for a cable or satellite set-top-box, and another remote unit for a multi-media system such as a video-cassette recorder (VCR), as well as a remote infra-red mouse, keyboard, and printer. Each of the target devices, such as the television, VCR and computer system, typically incorporates its own separate infra-red receiver circuit. With the addition of other devices such as a computer system or a palm-top, more infra-red remote units and infra-red receiving units will be added. Thus, a drawback to the prior art is that a consumer typically finds it necessary to use more than one receiver circuit to receive and process the different infra-red signals.
With reference to Prior Art FIG. 1, one prior art approach to address this drawback is illustrated. One set-top box 100 contains two infra-red receiver circuits, 120 and 130, which are located behind one transparent infra-red receiver window 110. Infra-red receiver circuit 120 receives infra-red signals from remote control device 105, and infra-red receiver circuit 130 receives infra-red signals from remote mouse 106 and remote keyboard 107. The remote control signal from infra-red receiver circuit 120 is transmitted through input/output (I/O) bus 125 to integrated circuit 150. The I/O bus 125 is connected to integrated circuit 150 using pin 144.
With reference still to Prior Art FIG. 1, the mouse signal from infrared receiver circuit 130 is digitized and transmitted through line 131 to PS/2 converter circuit 133, which converts the mouse signal into a signal conforming to the PS/2 communications standard. The mouse signal is then transmitted through I/O bus 135 to integrated circuit 150. Similarly, the keyboard signal is digitized and transmitted from infra-red receiver circuit 130 through line 132 to PS/2 converter circuit 133, where the keyboard signal is converted to the PS/2 communications standard. The keyboard signal is then transmitted through I/O bus 136 to integrated circuit 150. The I/O bus 136 is connected to integrated circuit 150 by two pins 140 and 141, and I/O bus 135 is similarly connected to integrated circuit 150 by two pins 142 and 143. Integrated circuit 150 decodes the remote control, mouse and keyboard signals so that the signals can be processed by a controller, such as a microprocessor (not shown).
The prior art approach illustrated by Prior Art FIG. 1 thus combines two infra-red receiver circuits into one set-top-box. However, a disadvantage to this prior art approach is that the set-top-box contains duplicate hardware. For example, there are two infra-red receivers, three I/O buses, and five pins. The duplicate hardware increases the cost of production and materials as well as the size of the integrated circuits within the set-top-box. As a result, the prior art approach described above is also at a disadvantage from the perspective of consumer preferences for lower prices and miniaturization.
With reference now to Prior Art FIG. 2, another prior art approach to address the drawbacks identified above is illustrated. This prior art approach is similar to the one described above in conjunction with Prior Art FIG. 1, but instead employs one infra-red receiver circuit 220 inside set-top-box 200 instead of two infra-red receiver circuits. The infra-red receiver circuit contains a filter that is capable of identifying the type of signal that is received from the infra-red remote unit. Depending on the type of signal, it then takes a different path through set-top-box 200.
With reference still to Prior Art FIG. 2, the remote control signal from infra-red receiver circuit 220 is transmitted through I/O bus 225 to integrated circuit 250. The I/O bus 225 is connected to integrated circuit 250 using pin 244. The mouse signal from infra-red receiver circuit 220 is transmitted through line 231 to PS/2 converter circuit 233, which converts the mouse signal into a signal conforming to the PS/2 communications standard. The mouse signal is then transmitted through I/O bus 235 to integrated circuit 250. Similarly, the keyboard signal is transmitted from infra-red receiver circuit 220 through line 232 to PS/2 converter circuit 233, where the keyboard signal is converted to the PS/2 communications standard. The keyboard signal is then transmitted through I/O bus 236 to integrated circuit 250. The I/O bus 235 is connected to integrated circuit 250 by two pins 242 and 243, and I/O bus 236 is connected to integrated circuit 250 by two pins 240 and 241. As with the first prior art technique, integrated circuit 250 decodes the remote control, mouse and keyboard signals so that the signals can be processed by a controller, such as a microprocessor (not shown).
Thus, the prior art approach described by Prior Art FIG. 2 eliminates one duplicate piece of hardware, i.e., one of the infra-red receivers, but still requires duplicates of some of the other hardware. Specifically, there are still three I/O buses and five pins on integrated circuit 250. Thus, as with the approach discussed above in conjunction with Prior Art FIG. 1, the duplicate hardware increases material and production costs and takes up space within the set-top-box, and therefore does not address consumer preferences.
Thus, a need exists for an electronic device that combines the cost-effectiveness of reduced hardware requirements with the convenience of a single set-top-box or other electronic product. A further need exists for an electronic device that provides efficient communication of infra-red signals received from remote units to the signal-decoding hardware for each of the infra-red remote devices. A still further need exists for an electronic device that satisfies the above needs and is compatible with existing infra-red remote units.
These and other objects and advantages of the present invention will become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the various drawing figures.